Single structure carton and blank



Sept. 3, 1968 T. w. FOSTER ET AL 3,399,820

SINGLE STRUCTURE CARTON AND BLANK Filed Sept. 16, 1966 2 Sheets-Sheet 1 llc INVENTORS THOMAS W. FOSTER DONALD P. NEMOEDE ATTORNEYS.

Sept. 3, 1968 T. W. FOSTER ET AL SINGLE STRUCTURE CARTON AND BLANK Filed Sept. 16, 1966 2 Sheets-Sheet 2 THQMAS W. FOSTER DONALD P NEMOEDE G J ATTORNEYS United States Patent 3,399,820 SINGLE STRUCTURE CARTON AND BLANK Thomas W. Foster, Palo Alto, and Donald P. Nemoede,

Santa Clara, Calif., assignors to Fibreboard Corporation, San Francisco, Calif., a corporation of Delaware Filed Sept. 16, 1966, Ser. No. 579,925 14 Claims. (Cl. 22937) ABSTRACT OF THE DISCLOSURE A single structure frozen food carton comprises top and bottom closures each having two outer flap portions sealed over intermediate inner flap portions. The inner flap portions are staggered to provide enhanced sealing characteristics.

This invention relates to a single structure carton and more particularly relates to a leakproof carton formed out of a single sheet of paperboard or like material.

The packaging of frozen foods and like commodities requires a leakproof carton which may be readily opened to dispense the cartons contents. The availability of heatsealable adhesives or coatings, such as polyethylene, has encouraged the packaging art to look towards the utilization of a one-piece carton for such packaging purposes. It has been found difiicult to construct and arrange a onepiece carton blank so as to effectively seal the end closures and other areas of the formed carton which are prone to leakage. Such leakage generally occurs at those areas of the carton whereat superimposed panels of the carton form unsealed pockets adjacent edges thereof.

The blank and formed carton of this invention provide cut and scored flaps and panels uniquely constructed and arranged to provide a high resistance to leakage when folded and sealed into position. In addition, means are provided for expeditiously opening the sealed carton.

An object of this invention is to provide a cut and scored carton blank which may be expeditiously and economically formed into a leakproof carton.

A further object of this invention is to provide a carton having cuts and scores constructed and arranged thereon to afford an extremely high resistance to leakage and contamination.

A still further object of this invention is to provide a carton having means formed thereon to expeditiously open such carton.

Further and more specific objects of this invention will i become apparent from the following description and accompanying drawings wherein:

FIG. 1 is an isometric view of a sealed carton made pursuant to the teachings of this invention;

FIG. 2 is a top plan view of a blank utilized to form the carton illustrated in FIG. 1;

FIG. 3 is an isometric view illustrating a tube formed out of the blank illustrated in FIG. 2; and

FIG. 4 is a view taken in the direction of arrows 4-4 in FIG. 1 with portions of the cartonremoved to more clearly disclose end closure constructions and arrangements of the carton.

Referring to FIG. 1, a carton embodying novel aspects of this invention is illustrated in its sealed condition. The apparatus and method disclosed in US. Patent No. 3,248,843, assigned to the assignee of this invention, comprise heat sealing techniques which may be utilized to form and seal the end closures of the carton illustrated in FIG. 1. The cartons blank, illustrated in FIG. 2 is preferably fully coated on each side with a laminant plastic such as polyethylene, polyvinylidene chloride or other suitable heat sensitive coatng. Such coating functions as a moisture barrier and seal at critical areas of the carton and also provides means for adhesively securing flaps and 3,399,820 Patented Sept. 3, 1968 panels together pursuant to applicable heat sealing techniques.

The blank preferably comprises in series a manufacturers glue fiap 11, a first end panel 12, a first side panel 13, a second end panel 14, and a second side panel 15, all hingedly connected together at parallel first scorelines 16-19. Parallel second scorelines 20-23 are arranged transversely with respect to the first scorelines to thus aid in defining carton flaps adapted to be folded into superimposed position and sealed together to form carton end closures. Flap 11 has flap portions 11a and 11b defined thereon by scorelines 16, 20 and 21, Scorelines 20-23 are preferably discontinued at areas 20a-23a, respectively, to effect a tight seal between flap 11 and panel 15 as will be hereinafter more fully explained.

A first carton end closure flap, adapted to form a gusset fold, comprises a triangularly shaped portion 12a hingedly connected to end panel 12 at scoreline 21. Flap portion 12a is defined by converging scorelines 12b and which further define flap portions 121! and 12e along with scorelines 16, 17 and 20. A scoreline 12] is arranged intermediate and parallel with respect to scorelines 16 and 17 to aid in defining additional flap portions 12g and 12h. As will be hereinafter more fully described, one of the unique features of this invention is the construction and arrangement of edges 12i and 12 of flap portions 12g and 12h, respectively. In particular, these edges are arranged parallel to first scorelines 20-23 and in staggered or stepped down relationship to edges of adjacent flaps to aid in effecting a leakproof end closure. Panel 13 has a second closure flap comprising portions 13a and 13b hingedly connected thereto by scorelines 20 and 21.

It should be noted that diverging scorelines 12b and 120 of the first closure flap are preferably arranged to intersect scoreline 21 of the second parallel scorelines, but are further arranged to terminate a short distance from scorelines 16 and 17, respectively, of the first parallel scorelines. Such distance may constitute one-sixteenth of an inch, for example. This gusset fold arrangement, wherein the apex of flap portion 12a intersects scoreline 20 but the base portion thereof does not intersect scorelines 16 and 17, functions to relieve corner pressures which are normally encountered during folding of panels 12-14 and their connected flap portions at scorelines 17 and 18. In addition, it has been found that the formed end closures of the carton (the bottom closure in FIG. 1) will assume a flatter configuration than is achieved normally when the scorelines 12b and 12c are extended to intersect scorelines 16 and 17, respectively.

The third and fourth closure flaps connected to second end panel 14 and second side panel 15, above scoreline 21, are substantially identical to the corresponding flaps connected to the first end panel and first side panel, respectively. Like subscript letters have been used to depict identical structures for the corresponding flaps. In addition, scorelines 20-23 are preferably discontinued at areas 20a-23a, respectively, to aid in effecting a positive seal at edge 110 of fiap 11. In particular, unscored areas 20a, 21a, 22a and 230 on flap 11 will be arranged to underlie unscored areas 20b, 21b, 22b and 23b, respectively, when the flap is secured to panellS.

The construction and arrangement of the bottom closure of the carton, arranged below scoreline 22, is identical to the above-described top closure, and, therefore, will not be discussed in detail.

In order to open the closed carton, opening means preferably comprising a substantially triangularly shaped flap is formed in panel 15. A tab 15d may be suitably connected to the apex of removable flap 15c by a scoreline 15e to facilitate manual grasping thereof. First diverging cuts or cut means 15 and 15g, defining flap 150, are arranged to extend from adjacent the intersections of scorelines 19 and 21 and scorelines 19 and 22, respectively, towards tab 15a. The cuts are preferably formed to a limited depth on the outer surface of panel 15 and each cut is arranged in adjacent and substantially parallel relationship with respect to each cut of second cut means 15h and 15i. Cuts 1511 and 15i are also formed to a limited depth on the inner surface of panel 15 and arranged in the manner illustrated to cooperate with the first cut means to open flap 150, as partially illustrated in FIG. 1.

It should be noted that perforations or cuts formed through the entire thickness of panel 15 would tend to induce leakage thereat. With the above-described opening arrangement only the portion of such arrangement which is arranged adjacent to tab 15a in FIG. 2 need be sealed. In addition, the arrangement of triangularly shaped flap 15c provides for a substantial exposure of the contents retained in the carton when the flap is lifted from panel 15. Cuts 15f15i may be formed to a depth approximating one-half of the thickness of panel 15 or to a lesser depth, depending upon the particular carton application. For example, such cuts have been found to provide an extremely clean and expeditious tear when they are arranged to merely cut through a plastic coating, such as polyethylene. Also, it should be understood that the opening means could be formed on one or more of panels 12-15 and/or arranged to extend transversely relative to the disposition illustrated in FIG. 2.

Generally, manufacturers glue fiap 11 (FIG. 2) will be secured to panel 15 prior to shipping of the partially formed carton to a packaging plant. Thus, the cartons may be shipped in a flattened, tubular condition. As above mentioned, flap 11 is preferably positioned under the edge of panel 15 so that unscored areas 20a-23a are arranged to underlie unscored areas 20b-23b, respectively. Such an arrangement permits the superimposed, unscored areas to be sealed withplanar surfaces of flap 11 and panel 15 maintained in close contact to prevent leakage thereby. On the other hand, if scores 2023 were continued through such panels it can be seen that leakage might occur along the score beads adjacent edge 11c of flap 11. In addition, a cut arrangement lle is preferably formed to a limited depth on flap 11 to permit tab 15d which is secured therein to initiate a clean tear.

It is desirable to provide a limited extension of scores 20-23 into flap 11 to permit proper folding when the carton is formed. The scores may extend, for example, for approximately one-half of the width of flap 11. It should be understood that manufacturers glue flap 11 may be connected to panel 15 in FIG. 2 rather than to panel 12. Also, in certain carton applications it may prove desirable to dispense with this flap and utilize suitable tape or other conventional securing means for attaching panels 12 and 15 together.

Once the carton has been opened to its FIG. 3 condition, suitable mechanisms may be employed to sequentially fold and seal the cartons top and bottom closures to the condition illustrated by the top end closure in FIG. 1. Hot air or other suitable heating medium may be imparted onto opposed surface portions of the end closure flaps to at least partially melt the adhesive thereon. The flaps can be subjected to pressure rollers or the like to effect sealed end closures. It should be noted in FIG. 2 that manufacturers glue flap 11 is extended at both ends thereof to a height substantially equalling the height of the closure flaps connected to side panels 13 and 15. This arrangement is desirable to facilitate full control of the manufacturers glue joint in a hot air sealer of the type employed in the apparatus disclosed in the above-mentioned US. Patent No. 3,248,843. In particular, such extension affords a physical support for the carton when it it maintained in the heat sealer so that the carton will not be unduly stressed when it is subjected to heat and pressure.

FIG. 4 illustrates the novel arrangement of the corners of the completed end closure which effects a tight seal thereat. Flap portions 13a and 13b have been removed to clearly illustrate such arrangement. At one end of the end closure it can be seen that edge 14j of flap portion 1412 is arranged below the top and parallel edge of flap portion 15b. Also, edge 14i of flap portion 14g is stepped down to a position below edge 14i. Thus, when flap portion 13b is secured thereon the composite thickness thereunder is gradually stepped down (moving upwardly in FIG. 4) from four thicknesses, to three thicknesses and to two thicknesses of paperboard. The heat will effectively seal the corners of the end closure, primarily due to flow of the melted adhesive into the rather small cervices formed by the stepped down edges of the above-described flap portions. A staking wheel is preferably employed to apply sealing pressure over critical edges of the sealed flap portions which are prone to leakage. Such staking wheel may comprise opposed rotary pressure wheels having raised portions or stakes suitably formed thereon. For example, four such stakes could be arranged to apply sealing pressures adjacent edges 12i, 12 141' and 14j whereas two additional stakes could be arranged to seal transversely thereof, i.e., across such edges.

The other end of the end closure is substantially identical to the one described above except that the stepped down feature involves five superimposed flap portions. In particular, edges 11d, 12: and 12 are arranged in stepped down relationship with respect to each other, between flap portions 13b and 15b, to avoid an abrupt change in paperboard thickness when the latter flap portions are sealed together. In addition to efiicient sealing desideraturn, it should be noted that such a stepped down arrangement does not require the precise alignment generally required for conventional carton end closures. Both the top and bottom closures are preferably glued or otherwise suitably sealed to the flattened condition illustrated by the formed bottom end closure in FIG. 1. It should be noted that diverging cuts 15f-15i could be formed in an arcuate manner rather than the linear manner illustrated in FIG. 2.

We claim:

1. A carton comprising opposed side and opposed end panels connected together by parallel scorelines and top and bottom closures, at least one of said top and bottom closures comprising a plurality of superimposed and connected flap portions defining substantially parallel edges arranged in stepped down relationship with respect to each other so that all of the edges of adjacent flap portions between said side panels at least one of said end panels are spaced from each other in nonccincident relationship.

2. The invention of claim 1 wherein said at least one of said top and bottom closures comprises a gusset fold at each end thereof.

3. The invention of claim 1 wherein said plurality of superimposed and connected fiap portions comprise two outer flap portions and two inner flap portions arranged between said outer flap portions, the edges of said inner fiap portions arranged in spaced relationship with respect to the edges of said outer flap portions and in spaced relationship with respect to each other.

4. The invention of claim 2 wherein said gusset fold comprises a triangularly shaped panel arranged between first and second of said first-mentioned parallel scorelines an defined by two converging scorelines arranged to intersect a first one of second parallel scorelines arranged transversely relative't'o said first-mentioned parallel scorelines and further arranged to intersect said second one of said second parallel scorelines but not the first and second of said first-mentioned parallel scorelines.

5. The invention of claim 1 further comprising opening means formed in one of said panels.

6. The invention of claim 5 wherein said opening means comprises removable flap means defined by first and second cut means formed on inner and outer surfaces of said one panel, respectively.

7. The invention of claim 6 wherein said first and second cut means each comprise first and second cuts formed to a limited depth into said one panel, said first cuts arranged in adjacent and substantially parallel relationship with respect to each other and said second cuts arranged in adjacent and substantially parallel relationship with respect to each other.

8. In a carton, a plurality of integral flap portions folded into superimposed relationship and defining substantially parallel edges arranged in stepped down relationship with respect to each other so that the edges of adjacent flap portions are spaced from each other in noncoincident relationship, said flap portions comprising two outer flap portions having two inner flap portions arranged therebetween, the edges of said inner flap portions arranged in spaced relationship with respect to the edges of said outer flap portions and in spaced relationship with respect to each other.

9. A one-piece carton blank comprising parallel first scorelines arranged to serially connect a first end panel, a first side panel, a second end panel and a second side panel and second parallel scorelines arranged transversely of said first scorelines to connect closure flaps to at least one end of each of said panels, the closure flaps connected to each of said side panels terminating in an edge arranged substantially parallel to said second scorelines, the closure flap connected to said second end panel terminating solely in staggered edges arranged substantially parallel to said second scorelines and in stepped down relationship therewith and also with respect to each other.

10. The invention of claim 9 wherein the closure flap connected to said second end panel comprises score means defining a gusset fold comprising a triangularly shaped panel arranged between first and second of said first parallel scorelines and defined by two converging scorelines arranged to intersect a first one of said second parallel scorelines, said converging scorelines further arranged to intersect said second one of said second parallel scorelines but not the first and second of said first parallel scorelines at a base of said triangularly shaped panel.

11. The invention of claim 9 wherein the closure flaps connected to each of said end panels each comprise score means defining a gusset fold arrangement adapted to be formed into a gusset fold when the blank is formed into a carton.

12. The invention of claim 9 further comprising a flap connected at one of said first scorelines to said first end panel, said flap arranged to terminate in an edge arranged coextensive with respect to the edges of the closure flaps connected to said side panels.

13. The invention of claim 12 whrein said first scorelines are further arranged to extend only partially into said flap short of a free edge thereof to provide first unscored areas thereon, said first scorelines further arranged to discontinue on said second side panel to provide second unscored areas thereon arranged to overlie said first unscored areas when said blank is formed into a carton with said flap secured to said second side panel.

14. The invention of claim 9 further comprising opening means formed in one of said panels, said opening means comprising removable flap means defined by first and second cut means formed to a limited depth on inner and outer surfaces of said one panel, respectively.

References Cited UNITED STATES PATENTS 2,246,755 6/1941 Reiter 229-17 2,973,086 2/1961 Thompson 206-45.31 3,021,002 2/1962 Guyer 221-63 X 3,054,680 9/1962 Mennen 229-51 3,185,375 5/1965 Thomas 229-17 3,189,246 6/1965 Seline 229-17 3,281,051 10/1966 OBrien et a1. 229-51 DAVIS T. MOORHEAD, Primary Examiner. 

